The explosive growth of the Internet, E-commerce, business critical network applications, and the convergence of voice, video and data, has made network performance and reliability central to the successes of most companies. Many companies today transmit and receive important data signals over the Ethernet data communication networks. An Ethernet communication network comprises a hub or PBX (private branch exchange) coupled to a channel and to many stations. The PBX receives data signals from stations and connects stations that are in communication with one another. Usually, in an Ethernet data communication network, backup electrical power is provided at each network center, but not at each local station because the cost to provide backup electrical power at each station is prohibitive. When companies are in the process of communicating to one another, power failure or even a brief power blackout would cause loss of critical information and great damage. Ethernet data communication networks follow the IEEE 802.3 standard in which electrical power is provided in-line with the data signals. The IEEE 802.3 standard requires that the Ethernet data communication networks use UTP (unshielded twisted pair) cables to transport data signals and electrical power together to provide power and data signals to each station. A similar arrangement exists for telephone loops from a central office.
To guarantee the reliability and quality of the data signals in an IEEE 802.3 af UTP Ethernet data communications link, engineers and technicians need to monitor the data signals and the electrical power of each communication port without disturbing the ongoing communication process of that port. To achieve that goal, engineers and technicians have to disconnect a port and insert in its place a measuring instrument to monitor the quality and reliability of that particular port, thus interrupting the communication process of that port. In addition, when a channel port is disconnected, electrical power to the station is also disconnected.
Therefore, there is a need for an apparatus that can provide electrical power to Ethernet data communication networks and to monitor the data signal quality of such networks without disturbing the communication process between stations.
There have been many attempts to solve and improve in-line power for signal activities for Ethernet data communication links, but none provides both the in-line power and monitoring signals at the same time without disturbing the communication process. In the U.S. Pat. No. 6,115,468 entitled “Power Feed for Ethernet Telephones Via Ethernet Link” by Maurillio Tazio De Dicolo (hereinafter ‘468 patent’), the inventor discloses an Ethernet device power transmission system that includes an input transformer, an output transformer, and a pair of twisted pair conductors. The input transformer includes a pair of primary windings for connection to a source Ethernet data, and a pair of secondary windings for connection to the Ethernet telephone line. Each transformer has a center tap. A first twisted pair conductor is connected across the first secondary, a second twisted pair conductor is connected across the second secondary and a DC-bias is provided between respective center taps of the first and second secondary. At the local end, an output transformer includes a first and a second center-tapped primary and a first and secondary connection to the load device. The first and second primary center taps are connected to a power processor for extraction of DC power. The '468 patent provides DC electrical power to the Ethernet line and overcomes the problem of net current flow that limits the choice of wire gauge. In this invention, the power is split into separate transmitting and receiving lines; and therefore, the power delivered to the load device is split equally over four wires. However, the invention in '468 patent does not monitor signal activities at the port; it only provides power for Ethernet telephones via an Ethernet link. In addition, each load of the apparatus described in the '468 patent needs a separate power processor, making this invention bulky and expensive.
Another attempt to solve signal monitoring and electrical power supply problems in an Ethernet data communication system is provided by U.S. Pat. No. 6,218,930 entitled “Apparatus and Method for Remotely Powering Access Equipment Over a 10/100 Switched Ethernet Network” by Boris Katzenberg, and Joseph A. Deptulla, (hereinafter '930 patent). The invention described in the '930 patent discloses an apparatus and method for remotely powering access equipment over a 10/100 switched Ethernet network comprising an Ethernet switch card with a phantom power supply for remote access equipment and added circuitry for automatic detection of remote equipment being connected to the network. The apparatus described in the '930 patent can only sense whether there is a remote apparatus connected to the system and provides a phantom power supply thereto. However, it cannot monitor the consistency of the power supply of a remote device and signal activities of a port. In other words, once the apparatus of the '930 patent detects a remote device and provides phantom power thereto, it cannot monitor whether there is a temporary power surge or not. When the power surge is sufficiently large, the apparatus of the '930 patent may mistakenly determine that the device has been disconnected and cut off the power to it. This may damage the remote device and cause a loss of critical signals. Finally, the apparatus of the '930 patent cannot monitor the data signals and the electrical power supply of the remote station.
Yet another attempt to solve the signal monitoring and electrical power supply problem for the Ethernet data communication system is found in the U.S. Pat. No. 6,140,911 entitled “Power Transfer Apparatus for Concurrently Transmitting Data and Power Over Data Wires” by David A. Fisher (hereinafter '911 patent). This invention provides an electric power supply to a network device across a transmission line. The patent discloses use of an electrical supply current sufficient to power a wireless access point. Power is transmitted concurrently with a network data signal across a transmission line. A power and data coupler couples the network data input and a power input respectively, and transmits the coupled signal, to a distance of three meters or more, over the transmission line to a power and data coupler. The power and data decoupler separates the power signal from the network data signal and supplies those signals to a power output port and a data output port, respectively, for use by a wireless access node. The power signal may be modulated at a low frequency relative to the frequency of the data signal. The electrical supply current of the invention described in the '911 patent does not tap into an in-line power supply to monitor and maintain a constant electrical power supply.
In conclusion, prior art technologies have improved in-line power supply problems. However, the prior art does not provide both an in-line DC electrical power supply to the Ethernet communication network and a monitor for data signals at the same time without disturbing the communication process. Accordingly, it is the object of the present invention to provide an apparatus that can provide both an in-line power supply and a monitor for data signals of an Ethernet data communication network without disturbing the communication process of such system.